Adjustable cam operated die head



Oct. 1 4, 1958 B. G. BJALME 2,855,611

ADJUSTABLE CAM OPERATED DIE HEAD I I Filed June 15, 1956 2 Sheets-Sheet 1 IN VEN TOR.

Oct. 14, 1958 B. G. BJALME 2,855,611

ADJUSTABLE CAM OPERATED DIE HEAD Filed June 15, 1956 2 Sheets-Sheet 2 United States Patent O 2,855,611 ADJUSTABLE CAM OPERATED DIE HEAD Bengt G. Bjalme, Erie, Pa., assignor to Reed Manufacturing Company, Erie, Pa., a corporation of Pennsylvania Application June 13, 1256, Serial No. 591,104

' 6 Claims. (Cl. 10-96) This invention is a quick opening pipe threader in which the chasers can be quickly and positively adjusted to thread different sizes of pipe with standard or over or under size threads. The selection of the size of the threads is positive and does not involve any judgment on the part of the user. Standard size is selected by a catch between the chaser opening and closing mechanism and the chaser cam member. Over or under size is selected by adjusting the position of the opening and closing mechanism relative to the cutter body.

In the drawings, Fig. 1 is a front view of a pipe threader partly broken away; Fig. 2 is a section on line 2-2 of Fig. 1; Fig. 3 is a back view of the threader partly broken away; Fig. 4 is a section of line 4-4 of Fig. 3; and Fig. Sis an edge view showing the connection between the guide and chaser cam members.

The threader has a front housing 1 with radial slots 2 for threading chasers 3. At the back of the housing 1 is fixed a housing 4 having radial slots 5 for guide members 6. The housings 1 and 4 are rigidly fastened together by bolts 7 and together comprise the frame of the threadcr. Journaled on the housing 4 is a chaser scroll plate 8 having spirally directed scroll projections 9 fitting in notches 10 in the threading chasers 3 so that as the chaser scroll plate is rotated, the threading chasers 3 are moved radially outward or inward depending upon the direction of rotation. A guide scroll plate 11 is rotatably carried on the guide housing 4 and has spirally directed scroll grooves 12 receiving tangs 13 on the guide members 6. As the guide scroll member 11 is rotated relative to the guide housing 4, the tangs 13 cooperate with the scroll grooves 12 causing radial inward croutward movement of the guide members depending upon the direction of rotation.

The chaser scroll plate 8 and the guide scroll plate 11 are connected together by a catch 14 fitting in a notch 15,

in the guide scroll member 11. The catch 14 is journaled on a pin 16 carried between ears 17 on the chaser scroll plate 8 and a coil spring 18 having one end 19 engaging the chaser'scroll plate and the other end 20 engaging the catch 14 urges the catch into the notch in the guide scroll plate 11. So long as the catch 14 is in the notch 15, rotation of the chaser scroll plate 8 causes a simultaneous rotation. of the guide scroll plate 11. When the guide members 6 come into contact with the outer surface of the pipe being threaded, rotation of the guide scroll plate 11 stops due to the resistance encountered to further inward movement of the guide members 6 and the spring 18 permits continued rotation of the chaser scroll plate 8 sufiicient to bring the threading chasers 3 into the desired threading position. While the outer surface of the pipe being threaded may vary in diameter, the thread cutting chasers 3 should cut the same size threads no matter how the outside diameter of the pipe may vary. The resilient connection between the guide chaser plate 11 and the thread chaser plate 8 permits simultaneous opening and closing of the chasersand guide members without interfering with the accuracy of the thread or requiring separate adjustment of the guide members so as to accommodate variations in the pipe diameter. The parts so far described are disclosed in greater detail in application Serial No. 519,084, filed June 30, 1955, now U. S. Patent No. 2,760,213 issued August 28, 1956.

In the use 'of the threader, there are'two adjustments yequired to meet all of the pipe threading requirements.

- shown in Fig. 3 to open and close the die.

2,855,611 Patented Oct. 14, was

First, it must be possible to open and close the threading chasers 3 at the beginning and end of the threading operations. Opening the threading chasers 3 permits quick removal of the threaded pipe while closing of the chasers returns the chasers to the threading position. This operation will be performed repeatedly while threading the same size pipe. The other operation performed is to move the threading chasers 3 radially to thread different sizes of pipe. This operation is performed each time the pipe size is changed. It is also desirable that the chasers be adjustable so as to cut over or under size threads. Cutting over size threads is necessary where the pipe is to be threaded into fittings which are over size. Cutting under size threads on the pipe is necessary when threading pipe which yields under the cutting stresses so that it is necessary to set the threading chasers for under size threads in order to end with a standard thread size.

The opening and closing of the threading chasers 3 and the simultaneous opening and closing of the guide members 6 is effected by a handle 21 pivoted at 22 on a link' 7 shown in Fig. 3, the chaser plate 8 has moved in a clockwise direction as viewed in Fig. 3 (counter-clockwise as' viewed in Fig. 1), thereby moving the threading chasers 3 radially outward While maintaining them concentric with the axis of the threadcr. When the handle is moved from the position shown in Fig. 3, the threading chasers 3 are moved radially inward to the proper threading position. From one aspect, the link 23 and crank arm or link 26 comprise a toggle movable between an extended position shown in Fig. 3 and a folded position with the handle 180 from the position shown in Fig. 3 to open and close the die. From one aspect, the link 23 and the crank arm or link 26 comprise a toggle movable between an extended position shown in Fig. 3 and a folded position with the handle 180 from the position Because the guide scroll member 11 is connected with the chaser scroll member 8, the guide members 6 move radially inward and outward with tthe threading chasers 3.

The pipe size adjustment which must be made every time the size of the pipe being threaded is changed is effected by changing the position of the shoe 29 with respect to the thread chaser scroll plate 8. The shoe 29 is journaled on the guide housing 4 and has an arcuate flange 30 which fits in an under cut groove 31 concentric with the axis of the threadcr. The shoe 29 has only a limited movement on the frame and need only have sufficient extent to provide adequate support. The shoe could be a complete ring. The chaser scroll plate is locked in fixed position with respect to the shoe 29 by means of a catch 32 urged by a coil spring 33 into any one of the angularly spaced notches 34 in the scroll plate 8. The catch can easily be moved out of the selected notch 34 by a handle 35. In a typical threader, the notches 34 would correspond to a range of pipe sizes for Which the thread pitch was the same such as from one to two inches. When the catch 32 is located in the selected notch 34, the thread chasers 3 are positioned to cut standard size threads for the size of pipe corresponding to the particular notch 34 selected. Smaller than standard size threads are cutby moving the handle 36 on the eccentric 25 in a clockwise direction as viewed in Fig. 1. The handle 36 has a ball detent 37 which cooperates with recesses 38 spaced apart one turn. Larger than standard size threads are cut by moving the handle 1 36 in a counter-clockwise direction as viewed in Fig. 1

until the ball detent 37 engages the selected recess 39. The recesses 39 are likewise spaced one turn apart. For the particular construction illustrated, it is possible to cut threads which are four turnsundersize or four turns oversize compared to standard pipe threads. A thread is said to be one turn oversize when it is tightened in one turn less than the standard thread.

From one aspect, the notches 34 in cooperation with the latch 32 permit coarse adjustment of the thread cutting chasers so as to change pipe sizes while the eccentric 25 actuated by the handle'36 permits fine adjustment of the threading chasers so that the cut thread will be over or under size the desired amount compared to standard pipe threads. These adjustments can be quickly made. Only a few seconds are required to change from one pipe size to'another. The accuracy of adjustment of the threading chasers 3 is very greatly improved over that which can be obtained by any' of the clamp type'adjustments. The notches 34 are precision machined at the factory so that whenever the catch 32 engages one'of the notches 34, the chasers 3 are accurately positioned for standard size pipe threads. The fine adjustment provided by the eccentric 25 and the ball detent 37 in cooperation with the recesses 38 or 39 likewise avoids any human error. The accuracy of the fine adjustment isdetermined at the point of manufacture rather than by judgment of the user in the field.

Compared to the conventional clamp type of adjustment, the adjustment for the present cutter can be made in about one-tenth of the time and much more accurately. With the standard clamp adjustment where the user matches index marks before tightening the clamp, the thickness of the usual index mark corresponds to the amount of adjustment applicant obtains by movement of the handle 36 between any two of the recesses 38 or 39. Applicant also can perform the adjusting operations quicker because there is no clamping screw to tighten.

The quick opening mechanism, i. e., handle 21, link 23, eccentric 25, crank arm 26 and shoe 29, is pivoted or guided on the frame 1 and always has the same relative position. Adjustments for pipe size are made by a catch between the shoe 29 and the chaser scroll plate 8. Adjustments for over or undersize thread are made by turning the eccentric 25. Neither of these adjustments affects the quick opening mechanism.

In use, the pipe size is selected by releasing latch 32 and turning the plate 8 relative to the shoe 29 (e. g., by turning plate 11) until the latch is received in the notch 34 corresponding to the pipe size; the desired amount, if any, of over or undersize of the thread is selected by the handle 36; and the die is opened and closed by the handle 21.

What is claimed as new is:

1. In a quick opening threading die of the type having a frame carrying radially movable thread cutting chasers, and a rotatable cam member for moving the chasers radially, an eccentric journaled in the frame, a handle for rotating the eccentric, a link havingone end pivoted on the eccentric at a point spaced from its center whereby the link is movable by the eccentric, a lever pivoted to the other end of the link and having a crank arm connected to the cam member for rotating the cam member relative to said link through an arc sufficient to open and close the chasers, the movement of the link by the eccentric providing a supplemental adjustment for the radial position of the chasers.

2. In a quick opening threading die of the type having a frame carrying radially movable thread cutting chasers and a rotatable cam member for moving the chasers radially, an eccentric journaled in the frame, a handle for rotating the eccentric, a link having one end pivoted on the eccentric at a point spaced from its center whereby the link is movable by the eccentric, a lever pivoted to the other end of the link and having a crank arm connected t he cam member for rotating the cam member relative to said link through an are sufficient to open and close the chasers, the connection between the crank arm and the cam member including latch means having interfitting parts engageable in any one of a plurality of positions corresponding to different sizes to be threaded.

3. In a quick opening pipe threading die of the type having a frame carrying a rotatable cam member for moving a plurality of angularly spaced thread cutting chasers radially in equal amounts so the chasers are always concentric with the axis of the die, a link, means anchoring one end of the link to the frame, a crank pivoted on the other end of the link, means connecting the crank to the cam member whereby pivoting the crank on the link causes rotation of the cam member on the frame relative to the link, and the anchoring means for the link including an eccentric journaled in the frame for moving the link angularly relative to the frame' 4. A quick opening threading die comprising a frame having a set of angularly spaced radial guideways receiving thread cutting chasers, a rotatable cam plate having spirally directed cam surfaces cooperating with the chasers to move them radially upon rotation of the cam plate relative to the frame, said cam plate and frame comprising members rotatable relative to each other about a common axis, a toggle connected between said relatively rotatable members, the toggle comprising a pair of links pivoted to each other and means for rotating the links between extended and folded positions each substantially tangent to an are centered on said common axis, the connection between one of the toggle links and one of the relatively rotatable members including latch means having interfitting detent parts engageable in any one of a plurality of angularly spaced positions with each of the spaced positions corresponding to a different size of pipe to be threaded.

5. In a quick opening threading die of the type having a frame carrying radially movable thread cutting chasers, and a rotatable cam member for moving the chasers radially, said frame and cam comprising relatively movable members, an eccentric journaled in one of the relatively movable members, a handle for rotating the eccentric, a toggle link having one end pivoted on the eccentric at a point spaced from its center whereby the link is movable by the eccentric, another toggle link pivoted to the other end of the first link and to the other of the relatively movable members, means for rotating the toggle links between extended and folded positions to open and close the die, the movement of the first toggle link by the eccentric providing a supplemental adjustment of the radial position of the chasers.

6. In a quick opening threading die of the type having a frame carrying radially movable thread cutting chasers, and a rotatable cam member for moving the chasers radially, said frame and cam comprising relatively movable members, an eccentric journaled in one of the relatively movable members, a handle for rotating the eccentric, a toggle link having one end pivoted on the eccentric at a point spaced from its center whereby the link is movable by the eccentric, another toggle link pivoted to the other end of the first link and to the other of the relatively movable member, the connection between the other toggle link and the other relatively movable member including latch means having interfitting parts engageable in any one of a plurality of positions corresponding to different sizes of pipe to be threaded, means for rotating the toggle links between extended and folded positions to open and close the die, the movement of the first toggle link by the eccentric providing a supplemental adjustment of the radial position of the chasers.

References Cited in the file of this patent UNITED STATES PATENTS 1,143,960 Hart June 22, 1915 1,804,708 Schurnacker May 12, 1931 1,848,297 Hyde Mar. 8, 1932 I 

